1. Field of the Invention
The present invention relates to a liquid fuel combustion apparatus and more particularly to improvement of or relating to a vaporized liquid fuel combustion apparatus of the type including a cylindrical combustion chamber in which liquid fuel is burnt to generate combustion gas, a blower for supplying combustion air into the cylindrical combustion chamber through a swirl flow guide port on the end plate disposed at the upstream end of the cylindrical combustion chamber and a heat exchanger by means of which thermal energy in the combustion chamber is transmitted to fluid to be heated so that the thus generated combustion gas flows forwardly in a swirled pattern through the cylindrical combustion chamber.
2. Description of the Prior Art
As is well known, a conventional vaporized liquid fuel combustion apparatus designed in smaller dimensions to achieve combustion under high operative load is adapted to generate swirl in the cylindrical combustion chamber for the purpose of improving combustion efficiency. To meet the requirement for improved combustion efficiency the conventional vaporized liquid fuel combustion apparatus is equipped with an air supplying tube disposed at a position eccentric relative to the axis of the cylindrical combustion chamber so as to allow combustion air to be supplied into the latter through the air supplying tube.
To facilitate understanding of the present invention a typical conventional vaporized liquid fuel combustion apparatus will be described below with reference to FIGS. 1 and 2.
As is apparent from the drawings, an U-shaped combustion air supplying tube 12 is attached to the cylindrical combustion chamber by welding in such a manner that the one end communicates with the discharge port of the blower and the other end projects inwardly of the cylindrical wall of the combustion chamber 10. As the blower 24, including motor 14, a rotor 16 driven by the former and a casing 22 with an air suction port 18 and air discharge port 20 formed thereon, is driven, combustion air is introduced into the cylindrical combustion chamber 10 via the air supplying tube 12. An ignition plug 26 is fixedly secured to the cylindrical combustion chamber 10. By virtue of arrangement of the combustion air supplying tube 12 made in the illustrated manner, a swirl as identified by a spiral line 28 in FIG. 1 is produced in the cylindrical combustion chamber 10. It has been often found with the conventional liquid fuel combustion apparatus that when the combustion air supplying tube 12 is incorrectly attached to the cylindrical combustion chamber 10, that is, when it is attached to the cylindrical wall of the combustion chamber as illustrated by dotted lines in FIG. 2, there takes place abnormality with respect to generation of swirl 28, resulting in poor combustion performance by the apparatus.
Other disadvantageous features of the conventional apparatus are that complicated welding tools and jigs and highly trained welding technique are required for carrying out uniform welding at the position where the end part of the combustion air supplying tube 12 is attached to the cylindrical wall of the combustion chamber 10 while the direction of projection of the combustion air supplying tube 12 into the interior of the combustion chamber 10 is correctly determined and moreover it is very difficult to achieve uniform welding to such a high level that there occurs no fluctuation in respect of combustion performance of the apparatus.